net: mvpp2: handle too large value in mvpp2_rx_time_coal_set()

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When configuring the MVPP2_ISR_RX_THRESHOLD_REG with the RX coalescing
time threshold, we do not check for the maximum allowed value supported
by the driver, which means we might overflow and use a bogus value. This
commit adds a check for this situation, and if a value higher than what
is supported by the hardware is provided, then we use the maximum value
supported by the hardware.

In order to achieve this in a way that avoids overflow and rounding
errors, we introduce two utility functions mvpp2_usec_to_cycles() and
cycles_to_usec(). Many thanks to Russell King for suggesting this
implementation.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

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This commit is contained in:

Thomas Petazzoni 2017-02-21 11:28:04 +01:00 • committed by David S. Miller

parent f8b0d5f8cc

commit ab42676af0

1 changed files with 29 additions and 2 deletions

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drivers/net/ethernet/marvell/mvpp2.c

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